1. Field of the Invention
The present invention relates to a device for manufacturing an organic EL element, and more particularly to cleaning equipment and cleaning method of a deposition mask for removing a deposition agent deposited on the deposition mask by laser, and collecting the deposition agent by a cyclone for recycling.
2. Description of the Related Art
Because of the thin and flat screen, the liquid crystal display device, the organic EL display device and the like have been increasingly demanded for the use as the flat display of the monitor and the TV. The organic EL display device with the light emitting feature exhibits an excellent view angle property. As the device needs no backlight, it is expected to be employed as the display in a wide variety of application fields.
The organic EL display device includes an organic EL layer formed of plural light emitting layers and a TFT for driving the organic EL layer to generate pixels arranged in a matrix so as to form a display region. The light emitting organic EL layer is formed in the pixel part through deposition on a planarizing film on the layer where the thin film transistor (TFT) is formed, or on the planarizing film on the layer where the TFT is not formed.
In the mainstream method of manufacturing the organic EL element, the deposition mask is employed for forming the pattern film. The element pattern is formed by heating and sublimating the deposition agent in the chamber so as to be deposited on the substrate through the opening of the deposition mask. The deposition agent is deposited on the portion of the deposition mask other than the opening. So the deposition mask is cleaned in accordance with the frequency for forming the film.
The wet type method employed for cleaning the deposition mask poses such problems as requiring longer processing time, increasing the environmental load owing to the use of the organic solvent, exerting damage to the miniature pattern, and making the collection and recycling of the deposition agent difficult. The dry type method using the laser has been developed to cope with those problems. JP-A No. 2006-192426 discloses the technology for cleaning the deposition mask by irradiating the laser thereto to separate the deposition agent so as to be immersed in ultrapure water and the organic solvent. JP-A No. 2006-169573 discloses the technology for collecting the deposition agent separated from the deposition mask coated with the adhesive film through which the laser has been irradiated to the mask.
The technology disclosed in JP-A No. 2006-192426 employs the laser to separate the deposition agent. However, there is no description with respect to collection of the separated deposition agent. JP-A No. 2006-192426 discloses the technology for immersing the mask in the ultrapure water or the organic solvent after separating the deposition agent from the mask for cleaning. In the disclosed case, it is difficult to collect the deposition agent.
In JP-A No. 2006-169573, the mask is coated with the adhesive film through which the laser is irradiated to the mask to separate the deposition agent therefrom, and the separated deposition agent is collected from the adhesive film. As the deposition agent is adhered to the adhesive portion of the film, the collection rate of the deposition agent is deteriorated. This may also cause the risk of mixing impurities such as the adhesive compound with the collected deposition agent.
The present invention is intended to realize the system structured to irradiate the laser to the mask for separating the deposition agent therefrom, and for collecting the separated deposition agent at a high collection rate while keeping high purity for recycling.